HPCC-9122 Add 'delimited' as s synonym for 'csv' in the dfuplus formats

For consistency with changes to the eclwatch user interface, dfuplus now
supports delimited as a synonym for csv.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
Merge pull request #4251 from richardkchapman/dfuplus-delimited

HPCC-9122 Add 'delimited' as s synonym for 'csv' in the dfuplus formats

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>